Improvement in pipe-wrenches



J. CRAIG.

- Improvement in Pipe-Wrenches.

No. 131,252. Ptented sep.1o,1s72.

1% 4a@ g W- `and the lever.

UNrrEE STATES PATENT OFFICE JOHN CRAIG, OF DETROIT, MICHIGAN.

IMPROVEMENT IN' PIPE-WRENCHES.

Specification forming part of Letters Patent No. 131,252, dated September 10, 1872.

lo whom it may concern:

Be it known that I, J OHN CRAIG, of Detroit, in the county of Wayne and State of Michigan, have invented a new and useful Improvement in SelfAdjusting Pipe-Wrenchesg and do declare that the following is a true and accurate description thereof, reference being had to the accompanying drawing and to the letters of reference marked thereon and being a part of this specification, in which- Figure l is a perspective view of my inlproved pipe-wrench, grasping a pipe 5 and Fig. 2 is a horizontal section of the wrench without the pipe.

Like letters refer to like parts in each gure.

This invention relates to a pipe-wrench so constructed that it vwill automatically grasp and hold cylindrical objects of various diameters and have a greater range of capacity than Vothers of its class, as heretofore constructed.

The invention consists in the peculiar construction and arrangement of the device and its severalparts, as more fully hereinafter set forth.

In the drawing, A represents a bar or lever having a curved jaw, A', at one end, convex on its face, and which maybe either of wroughtiron or a malleable casting. In the face of this jaw is inserted, by dovetailing it, a serrated .steel bit,`a. B is a curved hook, having a square shoulder at its outer end, and is pivoted to the lever A at b. This hook may also be of wrought or malleable iron; it is hinged or pivoted through ears B', which embrace the body of the lever at the commencement of its curve, the pivot b passing through both ears In the base of the hook there is drilled a hole, c, and in it is inserted a headed pin, d. Before the hook is pivoted to the lever the head of the piu bears against the edge of the lever, and between the head of the pin and the base of the hook a spiral spring, e, is coiled about the pin, the tendency of which spring is to close the hook' against the curved face of the lever, as seen in Fig. 2.

The operation of the wrench will be readily understood on reference to the drawing.

The form of the hook and its arrangement with relation to the curved jaw A are such that the smallest wrench used in the trade-to wit, that for turning one-eighth-inch pipewill also grasp an inch pipe, and so on through the larger sizes of wrenches, which cannot be done in other wrenches without adjusting one of the jaws for the purpose.

I do not wish to be understood as claiming that other wrenches require to be adjusted for each diameter of pipe, but that they cannot grasp pipes of such great difference in diameter as this can without adjustment 5 nor do I claim, broadly, a pivoted hook provided with a spring. Y

If the lever be made of malleable cast-iron the steel bit a may be dovetailed in, as dethe handle A having the jaw Al with bit a, as

described.

JOHN CRAIG.

Witnesses H. F. EEERTS, Crus. L. MEssMonE. 

